﻿#region License

// Copyright (c) 2009, Bill O'Neill (william.w.oneill@gmail.com)
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
// 1. Redistributions of source code must retain the above copyright 
// notice, this list of conditions and the following disclaimer.
// 
// 2. Redistributions in binary form must reproduce the above copyright 
// notice, this list of conditions and the following disclaimer in the 
// documentation and/or other materials provided with the distribution.
// 
// 3. Neither the name of Focal Point Technology Solutions, LLC nor 
// the names of its contributors may be used to endorse or promote 
// products derived from this software without specific prior written 
// permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
// CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
// OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 
// USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 
// DAMAGE.

#endregion

using System;
using System.Threading;

namespace X10d.Interface.States
{
	/// <summary>
	/// Verifies the checksum returned from the interface
	/// </summary>
	/// <typeparam name="TNextState">
	/// Next state to transition to upon success
	/// </typeparam>
	internal class VerifyChecksumState<TNextState> : PortStateBase where TNextState : IPortState, new()
	{
		private readonly byte[] mBufferToVerify;

		/// <summary>
		/// Creates a new instance of the class
		/// </summary>
		/// <param name="bufferToVerify">
		/// Reference to the original buffer sent to the device. Used to verify the checksum.
		/// </param>
		public VerifyChecksumState(byte[] bufferToVerify)
		{
			if (bufferToVerify == null || bufferToVerify.Length == 0)
			{
				throw new ArgumentException("Buffer to verify was null or empty");
			}

			mBufferToVerify = bufferToVerify;
		}

		/// <summary>
		/// Verifies the checksum returned from the interface
		/// </summary>
		/// <param name="requestManager">
		/// Reference to the request manager
		/// </param>
		/// <param name="newBuffer">
		/// New data received from the serial port
		/// </param>
		protected override void DoHandleNewBuffer(IRequestManager requestManager, byte[] newBuffer)
		{
			if (((mBufferToVerify[0] + mBufferToVerify[1]) & 0xFF) == newBuffer[0])
			{
				Log.Info("Checksum OK");

				requestManager.TransitionToState( new TNextState() );
			}
			else
			{
				Log.Warning("Checksum failed");

				requestManager.TransitionToState( new SendAddressState() ); 
			}
		}
	}
}